Can you really make this dimply fat disappear? One celebrity did. Here's how you can follow her lead.

Ask any woman: If there’s one thing that’s worse than fat, it’s dimply fat. After all, everyone hates cellulite. And that goes double for the ladies. Yes, this affliction plagues some men, but it’s far more prevalent in females. In fact, up to 98% of adult women have some degree of cellulite, according to a recent paper from Cornell University. Read: It doesn’t matter if you’re carrying around extra pounds or are as skinny as a model, cellulite could still be a problem—especially on your butt. (Looking for effective ways to tone up fast? Prevention has smart answers—get 2 FREE gifts when you subscribe today.)

Just ask actress Rachel Nichols, who stars in the action movie, Conan. Eight years ago, when Rachel was working as a model, she noticed that a cottage-cheese-like complexion began to appear on her backside. “I was a 23-year old model, but I didn’t work out or eat right,” she says. “I looked good in clothes, though.” Her strategy: Avoid making eye contact with her own butt. “You’re always told that cellulite is hereditary, and that there’s nothing you can do,” says Rachel. “You just have to live with it.” Or so she thought.

Soon after, Rachel landed a recurring role on the hit show Alias. That’s when she hired celebrity trainer Valerie Waters, who was already working with Jennifer Garner. “When we first met, Valerie said, 'You’re a little soft,’ ” recalls Rachel. “And she was right: I was skinny-fat.” But a few weeks later? “I started noticing that the cellulite was going away. And after several months, it had disappeared completely,” says Rachel. “No massaging, no strange equipment, no nonsense. Just hard work, 3 or 4 times a week, along with a good diet.” (Another cellulite-fighter? Dry brushing, which exfoliates skin and boosts circulation. Add Rodale's Merben Body Brush to your cellulite-fighting arsenal.)

While there are many theories to the actual cause of cellulite, one point that’s not disputed: It’s fat. So even if you’re still thin when cellulite starts to appear, the dimply area is likely the product of an increase in body fat. Think about it: A guy can be lean, but not have six-pack abs. The reason you can’t see his washboard is simply because a layer of fat is deposited just under the skin, hiding the muscle. That doesn’t have to equate to a beer gut, of course; softening up is a gradual process. And the midsection is the place where many guys seem to collect fat initially. For lots of women, fat tends to first accumulate on their butts and the backs of their thighs.

But that’s just one part of the problem. The other? The area where fat is stored under the skin seems to have a different structure than elsewhere on the body. And as those fat cells increase in size, this structural abnormality begins to become visible on the surface of the skin, leaving indentations. That’s cellulite. The more those fat cells inflate, the more evident the cellulite becomes. The flipside: Lose the fat; say goodbye to cellulite. Trouble is, just as the butt is often the first place fat starts to appear, it’s frequently the last place it disappears. Which may explain why it seems like you can’t shake the cellulite.

The truth is, consistency and patience are your friends. “In my experience, it can take up to a year for cellulite to go completely away,” says Valerie, who has also trained Cindy Crawford, Jessica Biel, and Sasha Alexander. “But it can start to get noticeably better within weeks. And that can be very motivating, which will help you stick with it.”

So what’s Valerie’s secret? “First and foremost, you have to eat a smart diet,” she says. “But you can get slower results or faster results, depending on how disciplined you want to be. There are different options for every lifestyle and goal.”

For those who want to zap cellulite fastest, Valerie recommends that you eliminate processed foods altogether. That includes foods that contain added sugar—soda, baked goods, and candy—as well as those products that have been highly refined, such as white bread, white pasta, and French fries. She also advises that you limit alcohol consumption to two drinks a week. The upshot: You eat a whole foods diet, with an emphasis on lean meats and fresh produce. “That doesn’t mean grilled chicken and steamed broccoli forever,” says Waters. “But six weeks of being super-dedicated can speed your results and give you the momentum to keep at it.”

Of course, Waters will tell you that her true expertise is using exercise to tone and tighten a woman’s butt and thighs. How does she do it? With fast-paced circuit-training that burns tons of fat, improves cardiovascular fitness, and strengthens every muscle in the body, especially targeting the glutes and hamstrings. Here’s a quick breakdown: A typical workout might be comprised of 3 separate circuits. Each circuit is usually 3 to 5 exercises. For the first circuit, you do one exercise after the next—around 10 to 15 reps of each—with no rest in between. Once you’ve completed all the exercises, you then rest for about a minute, and repeat the entire circuit one to two more times. When you’ve finished, you move on to the second circuit, and then the third, following the same procedure for each.

While Valerie makes sure you work your entire body, she has advises an important cellulite-squelching ratio: do two lower body exercises for every one upper body exercise. It’s an approach that’s supported by research. In a recent Syracuse University study, scientists found that people burned more calories the day after they did lower-body resistance training than the day after they worked their upper body. The likely reason: “Leg muscles—like your quads and glutes—generally have more muscle mass than those of your chest and arms,” says study author Kyle Hackney, PhD. “Work more muscle during your exercise session, and your body has to expend more energy to repair and upgrade those muscles later.”

So blend the breath-taking pace of a circuit routine with the metabolism-boosting benefits of weight work, and you’ll start to smooth out that orange-peel pattern on your rear end. What’s more, the improvement in strength and fitness you experience will allow you to work harder and harder each workout—dipping into your fat stores to torch even more calories, and achieve even faster results.

But there’s another motive behind Valerie’s exercise prescription. Many of the lower-body movements she advises zero-in on the glutes, or butt muscles. This is perhaps the modern woman’s most admired but also most neglected body part. That’s because even the leanest of women can have what’s known as “gluteal amnesia.” This is when too much sitting causes your glutes—your body’s largest muscle group—to forget how to fire. Combine this with a common postural problem called swayback, and the muscles becomes lax. The result: Your cheeks just hang there, or sag. Thanks a lot, gravity. The good news: By strengthening the muscles of your backside, you train your glutes to switch on again. And the end-payoff is what amounts to a butt lift, says Valerie. (No scalpel necessary.)

Valerie shares all her secrets in her book, Red Carpet Ready. These are the same strategies she used to help Rachel Nichols go from a self-professed “skinny-fat” girl to one of Hollywood’s hottest action-hero babes. But to get you started, we asked Valerie to share her three favorite butt exercises. Use these moves to target, tighten, and tone your tush for good.

Exercise 1: Single-leg Hip Raise

[A] Lie faceup on the floor with your left knee bent and your right leg straight. (Your right leg should be in line with your left thigh.) Now try to make your stomach as skinny as possible and hold it that way.

[B] Squeeze your glutes and raise your raise your hips until your body forms a straight line from your shoulders to your knees. (Your left leg should stay elevated the entire time.) Pause for 2 seconds, as you keep your tummy tight and continue to squeeze your glutes. Then lower back to the starting position and repeat. Key pointer: Your torso and hips should move as one unit. So the arch in your lower back should remain the same from start to finish. This way, you're primarily doing the work with your glutes, not your lower back and hamstrings.

If that’s too hard: Do the same movement, but with both feet on the floor.

If that’s too easy: Do the same movement, but cross your arms over your chest instead of bracing them against the floor (as shown).

Exercise 2: Reverse Lunge

[A] Grab a pair of dumbbells and hold them at arm’s length next to your sides, your palms facing each other.

[B] Step backward with your right leg, and lower your body until your left knee is bent at least 90 degrees and your right knee nearly touches the floor. Push yourself back to the starting position by pressing into the floor with your left heel. That's 1 rep. Do all your reps, then repeat with your right leg.

If that’s too hard: Try the exercise with just your body-weight.

Make it even better: Try the exercise with your back foot on a Valslide—the secret weapon Valerie uses with all her clients. The idea: Think of your back foot simply as a support, so that you’re keeping most of your weight on your front leg. The Valslide will help you do this better, and that’ll make your butt muscles work harder.

Exercise 3: Stepup

[A] Grab a pair of dumbbells and hold them at arm’s length at your sides. Stand in front of a bench or step that’s about knee-height, and place your left foot firmly on the step.

[B] Press your left heel into the step and push your body up until your left leg is straight and you’re standing on one leg on the bench, keeping your right foot elevated. Lower your body back down until your right foot touches the floor. That’s one repetition. Do all your reps with your left leg, then do the same number with your right leg.

If that’s too hard: Try the exercise with just your body-weight.

Add variety: Stand sideways, with your right leg next to step. Then cross your left foot in front of your right leg and place your left foot on the step. Now perform a stepup. Focus on really pressing your left heel into the step to push yourself up.

Bonus: The Best Exercise for Your “Bum Smile”

Never heard of the bum smile? "That’s what I call the line where your glutes meet your hamstrings," says Valerie. Here’s her pick for the best way to target that area.

The Exercise: Straight-leg Deadlift[A] Grab a pair of dumbbells with an overhand grip, and hold them at arm's length in front your thighs. Stand with your feet shoulder-width apart and knees slightly bent.

[B] Without changing the angle of your knees, bend at your hips (keep your lower back arched), and lower your torso until it's almost parallel to the floor [B]. Pause, then squeeze your glutes, thrust your hips forward, and raise your torso back to the start

Make it harder: Perform the exercise while balancing one leg. Do all your reps, then repeat with your other leg.